@claire, you can try out TAESK CMS by someone on this list, I checked it out and it looks very nice with a simple to understand and manage back-end unlike Kenya's favorite Joomla.It will give you the simplicity you need while offering you the opportunity to scale up in future. In quick steps you can add pages & content. 

Alternatively a skunk here could customise for you the Taesk at a half your budget and the other half donate to the brains behind Taesk.